Various benefit agents, such fragrances, are expensive and/or difficult to deliver as neat liquids as they exhibit high volatility, and rapidly lose their aroma if left exposed to the atmosphere. As a result, fragrances have been microcapsulated. That is, sealed inside a capsule, to enable the aroma to be retained. However, even if a benefit agent such as a highly volatile fragrance is sealed within a microcapsule, the fragrance still can escape through gaps within the microcapsules cell wall. Thus, long term storage, particularly in the presence of other materials, is a problem. A technique described in Japanese Laid-Open Publication No. Hei 9-911, wherein a volatile substance is encapsulated by incorporation within a gel-like polyurethane resin, attempts to solve this problem. In this technique, during the capsulation process, a polyfunctional isocyanate and a polyol are reacted together to produce a gel-like polyurethane resin, and the volatile substance is incorporated within this polyurethane resin. Thus, while not being bound by theory, it is believed that release of the volatile substance from the capsule core is suppressed. Unfortunately such technique employs isocyanate which can produce an irritating odor that detracts from benefit agents, particularly the aroma of the fragrance. In addition, improvement is also desirable in terms of the fact that the proportion of the polyurethane resin in the encapsulated material at the core is quite high relative to the quantity of the target volatile substance. Such an improved microcapsule is particularly desirable as consumers typically associate the odor of a cleaned or treated article with the degree of cleanliness or freshness of such article.
Accordingly, the present invention provides a microcapsule which is able to stably retain a volatile substance for an extended period, in the presence of other materials, such as consumer product formulations. Such microcapsule is particularly suitable for encapsulating fragrances and the like. In addition, consumer products, including cleaning and/or treatment compositions that contain the aforementioned microcapsules and processes of making and using same are disclosed.